DE1933747B2 - COMBUSTIBLE SOLIDS MIXTURE FOR THE PRODUCTION OF CARBON DIOXYDE - Google Patents

Description

3 4

where M is an alkali metal (for alkaline earth metals this results in both the reaction rate and slightly different equations) χ which is the temperature as well as the generation of carbon valency of M and M ^{1 are} an alkaline earth metal. Dioxide can be reduced. The amount of carbonate, which can be added to the mixture without adversely affecting the solid mixture with an organic carbonate, is one that decomposes endothermically, whereby the decomposition temperature is a function of of carbonate. The appropriate choice of the size of the additive, taking into account the decomposition temperature, should increase the combustion temperature very precisely, taking into account the thermal decomposition temperature of the carbonate used in the mixture containing the carbonate. Conveniently, carbonates, which control the combustion process and thus the xo decompose at temperatures of about 300 to 400 ° C., can be added per unit of time, in amounts up to that which one mole of CO ₂ generated for

It has also proven to be advantageous if the every mole of CO ₂ generated by the peroxide-carbide reaction

Solid mixture a smaller amount, preferably tion is generated. Carbonates can also be added

about 5 to 10 percent by weight boric acid or boron 15 are mixed, which dissociate or dissociate ^{at about 800 ° C.}

Oxyd contains, as this mixed constituent, the re-disintegrate, in amounts up to that which

absorption of the CO ₂ by the reaction products generates about a quarter MoI CO ₂ , for each

largely prevented. Moles of CO ₂ produced by the peroxide-carbide reaction

Suitable peroxides are the alkali metal peroxides that are produced. The carbonates can be powder form,

for example lithium peroxide Li ₈ O ₂ ; Potassium peroxide in crystal form or another finely divided form

K ₂ O ₂ ; and sodium peroxide Na ₂ O ₂ . Also have alkali.

metal superoxides, for example sodium superoxide. It is essential that the mixtures be anhydrous

NaO ₂ and potassium _{superoxide KO 2} ; also alkaline earth, so that none of the constituents are absorbed

metal peroxides, for example calcium peroxide CaO ₂ water or water of hydration, the

and barium peroxide BaO ₂ ; Furthermore, alkaline earth metal mixtures must also be used during storage prior to the

super oxides, for example calcium superoxide CaO ₄ . Water vapor in the atmosphere must be protected.

Sodium or potassium peroxide reacts with the peroxides because of water, with oxygen

preferred because of their high oxygen content. Sodium is formed, and with the carbides, with acetylene

or calcium peroxide are expediently standing, which, albeit slowly, possibly

used when CO ₂ explosive mixtures can be formed at the lowest cost. the

should be produced and if a lesser production of the substances concerned are therefore in a dry place

supply of CO ₂ per unit weight of the burning atmosphere mixed, pressed and packaged.

Substance is permitted. The peroxides can be in powder- some constituents contain impurities that

form or in granular form or disintegrate at the combustion temperatures and

in the case of KO ₂ and Na ₂ O ₂ in the form of flakes, give off water, e.g. B. commercial calcium

which arise when the metal is sprayed in air, carbide, which contains a considerable amount of extinguished

as described in US Pat. No. 2,4 05,580. Lime contains Ca (OH) ₂ . Such impurities

Suitable carbides are alkaline earth metal carbides, the mixtures are not consumed during storage

for example calcium carbide CaC ₂ , magnesium carbide adversely affects, but they are the reason for the

MgC ₁ and barium carbide BaC ₂ ; furthermore aluminum formation of a flame with a short duration, which in

carbide Al ₄ C ₃ . Calcium carbide may be undesirable because of its specific application,

price and its high carbon content. Commercially available calcium carbide is used,

preferred. The carbides can be in powder form, so the slaked lime is expediently carried through

granular form or in any other fine heating in a vacuum to high temperatures, e.g. B.

distributed form can be used. 45 to about 438 C, whereupon the vacuum breaks through

All inorganic carbonates can be _{replaced in a CO 2} atmosphere to the extinguished

which thermally convert lime into calcium carbonate without melting. Are the

fall, such as B. Magnesium carbonate, Calciumkarbo- used ingredients essentially free of

nat, cesium carbonate, rubidium carbonate, cobalt impurities, so that no water is

carbonate, nickel carbonate and zinc carbonate. Magnetic combustion occurs, so the mixtures burn with it

Carbonate is preferred because it has a flameless combustion front created by the

has a high carbon dioxide content and goes out if the ignition point is lower.

Temperature decays. In small pieces, on the order of

Preferably the peroxides and the carbides are about 10 g, the peroxide-carbide mixtures are used with in stoichiometric proportions in order to achieve the 55 or without carbonate, up to about 95 % carbon dioxide highest yield of carbon dioxide. It off. For larger pieces of compact, for example with a though other ratios or proportions may weight of 100 grams to several kilograms or be used as the stoichiometric, so as to the CO ₂ yield is substantially lower, however, no further special advantages such distance. B. about 60%, due to the reabsorption. Mixtures which only hold peroxides and carbides from the carbon dioxide through already burned parts of the mass burn very quickly and compactly after ignition. The loss is reduced by reabsorption at a high temperature, so that carbon is generated very quickly by adding a smaller amount of boron dioxide. acid to the mixture largely eliminated because

The reaction rate and the temperature thereby make the solid reaction products from crystalline

can be added to the mixture thermally 65 components that absorb carbon dioxide in

disintegrating inorganic carbonate is moderated to be converted to vitreous components that

the. The endothermic decay absorbs heat carbon dioxide does not absorb. The addition of

from the exothermic peroxide-carbide reaction, about 5 to 10% by weight boric acid leads to a carbon

Dioxide yield from 70 to 80%. Larger amounts of boric acid can be used, e.g. B. up to 20% or more, whereby the yield can still be increased slightly, but at the expense of the amount of CO ₂ that is generated per unit weight of the burning mixture.

The necessary to compress the materials into a coherent compact mass Pressures will vary and depend on the particular ingredients chosen, but they will range expediently generally between about 840 and 1400 kg / cm *.

The invention is illustrated below by means of examples further explained:

example 1

Commercially available granular calcium carbide was heated in vacuo at about 427 ° C for 2 hours to break down the slaked lime. _{CO 2} was then introduced into the vacuum, converting the slaked lime into calcium carbonate. 2.8 g of the pretreated carbide (75% CaC ₂ ) and 7.9 g of flaky KO ₂ were mixed and compressed with a pressure of about 1050 kg / cm ² to form a coherent body. This was electrically ignited using a BaCrO ^ Zr primer, whereupon 1.411 of essentially pure CO _{2 was} rapidly given off, ie 0.13 liters per gram of the combustible mixture.

Example 2

Example 1 was repeated using 28 g of pretreated carbide and 79 g of KO ₂ . The compact mass burned with the ignition

a combustion front, which had a velocity of about 10 cm / min, giving off 9.5 liters of CO ₂ , ie 0.09 liters per gram of the combustible mixture.

Example 3

An intimate mixture was formed from 28 g of pretreated carbide, 79 g KO ₂ and 85 g MgCO ₃ and pressed together with a pressure of 1050 kg / cm * in order to form a coherent body, which after ignition at a speed of about 5 cm / min burned off, releasing 17.31 CO ₂ , ie 0.09 l / g of the combustible mixture.

Example 4

An intimate mixture was produced from 75 g of pretreated calcium carbide, 210 g of KO ₂ , 150 g of MgCO ₃ and 18 g of B ₂ O _{3, which was}

ao cm ^{2 was} compressed to form a coherent body which after ignition burned off at a rate of about 5 cm / min, releasing 461 CO ₂ , ie 0.11 l / g of the combustible mixture.

as compositions in which other peroxides, Carbides or carbonates are used, burn off essentially in the same way as those after the above Examples, except for compositions containing lithium peroxide, in which the burn rate is about 25% lower.

The substances according to the invention are particularly suitable for the production of carbon dioxide in transportable Devices such as B. fire extinguishers, inert gas blankets and other fire extinguishing equipment.

Claims (4)

r. Brennuagsvorgang using the Luftsauer- patent claims: substance can be produced, on the other hand, no suitable source of carbon dioxide has been available up to now. 1. Combustible solid mixture for production Based on this state of the art, the of carbon dioxide, thereby marked- 5 the present invention is therefore based on the object draws that they from a solidified a combustible solid mixture for the production of The body consists of an evenly distributed carbon dioxide that is roughly in the nature of the propose Oxide from the group of alkali metal peroxides, known chlorate candles for the production of acidic alkali metal peroxides, Alkaline earth metal peroxides the desired gas in - based on the and alkaline earth metal superoxides and a carbide 10 weight the solid mixture - relatively large amount from the group of alkaline earth metal carbides and aluminum, in the course of a controlled abminium carbide contains, these constituents ongoing chemical process. essentially in stoichiometric proportions. This task is carried out by a flammable solid material, mixture dissolved according to the invention thereby 2. Mixture according to claim 1, characterized in that it consists essentially of one shows that it consists of an evenly distributed solidified body, which is an evenly inorganic one Contains carbonate, which, without being melted, is an oxide from the group of alkali metal peroxides, zen at a temperature below the alkali metal superoxides, alkaline earth metal peroxides and combustion temperature of the substance thermally cereal alkaline earth metal superoxides and a carbide from the falls. ao group of alkaline earth metal carbides and aluminum carbides 3. Mixture according to claim 2, characterized in that it contains these constituents in stoichiometric proportions draws that they are potassium peroxide, calcium components. contains carbide and a carbonate, the decomposition of which enables such a combustible solid mixture contains carbide and a carbonate, the decomposition of which it is necessary to do without pressure vessels, which are difficult temperature is below about 400 ° C, and that on as and are expensive, since numerous in their production every mole of potassium peroxide about a third mole of safety regulations must be observed, and Calcium carbide and about two-thirds moles of which is still no absolute security against one Carbonate come. Provide leakage or loss of pressure. Such a 4. Mixing after one of the preceding pressure losses can, however, result in very serious claims, characterized in that they have boron 30 parts, if the carbon dioxide for emergency oxide contains. Armor is often used for a long time be stored unused, like this is the case with fire extinguishers and gas bags, which used as safety devices in automobiles should be set. For these use cases is now The invention particularly relates to a combustible solids mixture according to the invention mixture for the production of carbon dioxide. suitable, especially since with their help the carbon As is well known, carbon dioxide becomes for different dioxide at a relatively constant rate Applications needed, whereby it can mostly be developed in what, for example, with enlargement Plants filled with pressure vessels and 40 turns of filled with liquid carbon dioxide in this the consumer is delivered, with pressure vessels only when using expensive reducers due to the fact that the gas can be reached under valves. According to the pressure prevailing in the pressure vessels flüsüigt, in these relatively large amounts of gas of the invention consists in the fact that they transport without energy permit. The US Patent 18 63 157 45 feed continues to burn once it is at least describes, for example, a method for generating a point that is brought to its ignition temperature. of carbon dioxide, in which acidic substances in this respect, the solid mixture is the cristalline Shape with a moisture-repellent familiar chlorate candles similar. The solid mixture Material of low melting temperature mixed and of according to the invention is for the practical use of this are encased and in which the thus treated set is placed in a container that has suitable acidic substances in contact with a carbonate outlet openings and ignition devices and out be brought, whereby the chemical reaction which the carbon dioxide after initiation of the intermediate these acidic compounds and the combustion process escapes. The ignition of the solid carbonate can be regulated by the temperature; the fabrics are heated. 55 sets are made, for example with the help of an electrical Another easy way to generate tric detonators, a heated wire or a of carbon dioxide consists in a gaseous or chemical source of heat. to burn gaseous hydrocarbons, the For the preparation of the solid mixture according to the Sauer invention necessary for the formation of the carbon dioxide are their constituents in fine Verstoff can be withdrawn from the atmosphere. One division mixed and then pressed to make a verartiges Method describes the US patent to produce solid bodies. 33 48 922, which result primarily from the enrichment When burning the solid mixture tion of the atmosphere of greenhouses with carbon- exothermic reactions, in the course of which carbon dioxide deals. dioxide according to the following equations For applications where the entry 65 is on the one hand: set of pressure vessels with liquid carbonic acid to xiMir ^ .firnxSMn j.iMmin would be cumbersome or too dangerous and in which 10MO ₈₁ + 3 M ¹ C ₂ -> 6CO ₄ + 5 M ₄ O ₁ + 3 M ¹ O (1) the CO, not even directly through a 5M ₁ O ₁₁ + M ¹ C ₈ - * 2CO ₂ + 5M ₂ O ₃ : + M ¹ O (2)